JSON-XS/XS.xs

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include "assert.h"
#include "string.h"
#include "stdlib.h"

#define F_ASCII        0x00000001
#define F_UTF8         0x00000002
#define F_INDENT       0x00000004
#define F_CANONICAL    0x00000008
#define F_SPACE_BEFORE 0x00000010
#define F_SPACE_AFTER  0x00000020
#define F_ALLOW_NONREF 0x00000080
#define F_SHRINK       0x00000100

#define F_PRETTY    F_INDENT | F_SPACE_BEFORE | F_SPACE_AFTER
#define F_DEFAULT   0

#define INIT_SIZE   32 // initial scalar size to be allocated

#define SB do {
#define SE } while (0)

static HV *json_stash;

// structure used for encoding JSON
typedef struct
{
  char *cur;
  STRLEN len; // SvLEN (sv)
  char *end;  // SvEND (sv)
  SV *sv;
  UV flags;
  int max_recurse;
  int indent;
} enc_t;

// structure used for decoding JSON
typedef struct
{
  char *cur;
  char *end;
  const char *err;
  UV flags;
} dec_t;

static UV *
SvJSON (SV *sv)
{
  if (!(SvROK (sv) && SvOBJECT (SvRV (sv)) && SvSTASH (SvRV (sv)) == json_stash))
    croak ("object is not of type JSON::XS");

  return &SvUVX (SvRV (sv));
}

static void
shrink (SV *sv)
{
  sv_utf8_downgrade (sv, 1);
#ifdef SvPV_shrink_to_cur
  SvPV_shrink_to_cur (sv);
#endif
}

/////////////////////////////////////////////////////////////////////////////

static void
need (enc_t *enc, STRLEN len)
{
  if (enc->cur + len >= enc->end)
    {
      STRLEN cur = enc->cur - SvPVX (enc->sv);
      SvGROW (enc->sv, cur + len + 1);
      enc->cur = SvPVX (enc->sv) + cur;
      enc->end = SvPVX (enc->sv) + SvLEN (enc->sv);
    }
}

static void
encode_ch (enc_t *enc, char ch)
{
  need (enc, 1);
  *enc->cur++ = ch;
}

static void
encode_str (enc_t *enc, char *str, STRLEN len, int is_utf8)
{
  char *end = str + len;

  need (enc, len);

  while (str < end)
    {
      unsigned char ch = *(unsigned char *)str;

      if (ch >= 0x20 && ch < 0x80) // most common case
        {
          if (ch == '"') // but with slow exceptions
            {
              need (enc, len += 1);
              *enc->cur++ = '\\';
              *enc->cur++ = '"';
            }
          else if (ch == '\\')
            {
              need (enc, len += 1);
              *enc->cur++ = '\\';
              *enc->cur++ = '\\';
            }
          else
            *enc->cur++ = ch;

          ++str;
        }
      else
        {
          switch (ch)
            {
              case '\010': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'b'; ++str; break;
              case '\011': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 't'; ++str; break;
              case '\012': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'n'; ++str; break;
              case '\014': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'f'; ++str; break;
              case '\015': need (enc, len += 1); *enc->cur++ = '\\'; *enc->cur++ = 'r'; ++str; break;

              default:
                {
                  STRLEN clen;
                  UV uch;

                  if (is_utf8)
                    {
                      uch = utf8n_to_uvuni (str, end - str, &clen, UTF8_CHECK_ONLY);
                      if (clen == (STRLEN)-1)
                        croak ("malformed or illegal unicode character in string [%.11s], cannot convert to JSON", str);
                    }
                  else
                    {
                      uch = ch;
                      clen = 1;
                    }

                  if (uch > 0x10FFFFUL)
                    croak ("out of range codepoint (0x%lx) encountered, unrepresentable in JSON", (unsigned long)uch);

                  if (uch < 0x80 || enc->flags & F_ASCII)
                    {
                      if (uch > 0xFFFFUL)
                        {
                          need (enc, len += 11);
                          sprintf (enc->cur, "\\u%04x\\u%04x",
                                   (int)((uch - 0x10000) / 0x400 + 0xD800),
                                   (int)((uch - 0x10000) % 0x400 + 0xDC00));
                          enc->cur += 12;
                        }
                      else
                        {
                          static char hexdigit [16] = "0123456789abcdef";
                          need (enc, len += 5);
                          *enc->cur++ = '\\';
                          *enc->cur++ = 'u';
                          *enc->cur++ = hexdigit [ uch >> 12      ];
                          *enc->cur++ = hexdigit [(uch >>  8) & 15];
                          *enc->cur++ = hexdigit [(uch >>  4) & 15];
                          *enc->cur++ = hexdigit [(uch >>  0) & 15];
                        }

                      str += clen;
                    }
                  else if (is_utf8)
                    {
                      need (enc, len += clen);
                      do
                        {
                          *enc->cur++ = *str++;
                        }
                      while (--clen);
                    }
                  else
                    {
                      need (enc, len += 10); // never more than 11 bytes needed
                      enc->cur = uvuni_to_utf8_flags (enc->cur, uch, 0);
                      ++str;
                    }
                }
            }
        }

      --len;
    }
}

#define INDENT SB \
  if (enc->flags & F_INDENT)            \
    {                                   \
      int i_;                           \
      need (enc, enc->indent);          \
      for (i_ = enc->indent * 3; i_--; )\
        encode_ch (enc, ' ');           \
    }                                   \
  SE

#define SPACE SB need (enc, 1); encode_ch (enc, ' '); SE
#define NL    SB if (enc->flags & F_INDENT) { need (enc, 1); encode_ch (enc, '\n'); } SE
#define COMMA SB \
  encode_ch (enc, ',');                 \
  if (enc->flags & F_INDENT)            \
    NL;                                 \
  else if (enc->flags & F_SPACE_AFTER)  \
    SPACE;                              \
  SE

static void encode_sv (enc_t *enc, SV *sv);

static void
encode_av (enc_t *enc, AV *av)
{
  int i, len = av_len (av);

  encode_ch (enc, '['); NL;
  ++enc->indent;

  for (i = 0; i <= len; ++i)
    {
      INDENT;
      encode_sv (enc, *av_fetch (av, i, 0));

      if (i < len)
        COMMA;
    }

  NL;

  --enc->indent;
  INDENT; encode_ch (enc, ']');
}

static void
encode_he (enc_t *enc, HE *he)
{
  encode_ch (enc, '"');

  if (HeKLEN (he) == HEf_SVKEY)
    {
      SV *sv = HeSVKEY (he);
      STRLEN len;
      char *str;
      
      SvGETMAGIC (sv);
      str = SvPV (sv, len);

      encode_str (enc, str, len, SvUTF8 (sv));
    }
  else
    encode_str (enc, HeKEY (he), HeKLEN (he), HeKUTF8 (he));

  encode_ch (enc, '"');

  if (enc->flags & F_SPACE_BEFORE) SPACE;
  encode_ch (enc, ':');
  if (enc->flags & F_SPACE_AFTER ) SPACE;
  encode_sv (enc, HeVAL (he));
}

// compare hash entries, used when all keys are bytestrings
static int
he_cmp_fast (const void *a_, const void *b_)
{
  int cmp;

  HE *a = *(HE **)a_;
  HE *b = *(HE **)b_;

  STRLEN la = HeKLEN (a);
  STRLEN lb = HeKLEN (b);

  if (!(cmp = memcmp (HeKEY (a), HeKEY (b), la < lb ? la : lb)))
    cmp = la - lb;

  return cmp;
}

// compare hash entries, used when some keys are sv's or utf-x
static int
he_cmp_slow (const void *a, const void *b)
{
  return sv_cmp (HeSVKEY_force (*(HE **)a), HeSVKEY_force (*(HE **)b));
}

static void
encode_hv (enc_t *enc, HV *hv)
{
  int count, i;

  encode_ch (enc, '{'); NL; ++enc->indent;

  if ((count = hv_iterinit (hv)))
    {
      // for canonical output we have to sort by keys first
      // actually, this is mostly due to the stupid so-called
      // security workaround added somewhere in 5.8.x.
      // that randomises hash orderings
      if (enc->flags & F_CANONICAL)
        {
          HE *he, *hes [count];
          int fast = 1;

          i = 0;
          while ((he = hv_iternext (hv)))
            {
              hes [i++] = he;
              if (HeKLEN (he) < 0 || HeKUTF8 (he))
                fast = 0;
            }

          assert (i == count);

          if (fast)
            qsort (hes, count, sizeof (HE *), he_cmp_fast);
          else
            {
              // hack to forcefully disable "use bytes"
              COP cop = *PL_curcop;
              cop.op_private = 0;

              ENTER;
              SAVETMPS;

              SAVEVPTR (PL_curcop);
              PL_curcop = &cop;

              qsort (hes, count, sizeof (HE *), he_cmp_slow);

              FREETMPS;
              LEAVE;
            }

          for (i = 0; i < count; ++i)
            {
              INDENT;
              encode_he (enc, hes [i]);

              if (i < count - 1)
                COMMA;
            }

          NL;
        }
      else
        {
          SV *sv;
          HE *he = hv_iternext (hv);

          for (;;)
            {
              INDENT;
              encode_he (enc, he);

              if (!(he = hv_iternext (hv)))
                break;

              COMMA;
            }

          NL;
        }
    }

  --enc->indent; INDENT; encode_ch (enc, '}');
}

static void
encode_sv (enc_t *enc, SV *sv)
{
  SvGETMAGIC (sv);

  if (SvPOKp (sv))
    {
      STRLEN len;
      char *str = SvPV (sv, len);
      encode_ch (enc, '"');
      encode_str (enc, str, len, SvUTF8 (sv));
      encode_ch (enc, '"');
    }
  else if (SvNOKp (sv))
    {
      need (enc, NV_DIG + 32);
      Gconvert (SvNVX (sv), NV_DIG, 0, enc->cur);
      enc->cur += strlen (enc->cur);
    }
  else if (SvIOKp (sv))
    {
      need (enc, 64);
      enc->cur += 
         SvIsUV(sv)
            ? snprintf (enc->cur, 64, "%"UVuf, (UV)SvUVX (sv))
            : snprintf (enc->cur, 64, "%"IVdf, (IV)SvIVX (sv));
    }
  else if (SvROK (sv))
    {
      SV *rv = SvRV (sv);

      if (!--enc->max_recurse)
        croak ("data structure too deep (hit recursion limit)");

      switch (SvTYPE (rv))
        {
          case SVt_PVAV: encode_av (enc, (AV *)rv); break;
          case SVt_PVHV: encode_hv (enc, (HV *)rv); break;

          default:
            croak ("encountered %s, but JSON can only represent references to arrays or hashes",
                   SvPV_nolen (sv));
        }
    }
  else if (!SvOK (sv))
    encode_str (enc, "null", 4, 0);
  else
    croak ("encountered perl type (%s,0x%x) that JSON cannot handle, you might want to report this",
           SvPV_nolen (sv), SvFLAGS (sv));
}

static SV *
encode_json (SV *scalar, UV flags)
{
  if (!(flags & F_ALLOW_NONREF) && !SvROK (scalar))
    croak ("hash- or arrayref expected (not a simple scalar, use allow_nonref to allow this)");

  enc_t enc;
  enc.flags       = flags;
  enc.sv          = sv_2mortal (NEWSV (0, INIT_SIZE));
  enc.cur         = SvPVX (enc.sv);
  enc.end         = SvEND (enc.sv);
  enc.max_recurse = 0;
  enc.indent      = 0;

  SvPOK_only (enc.sv);
  encode_sv (&enc, scalar);

  if (!(flags & (F_ASCII | F_UTF8)))
    SvUTF8_on (enc.sv);

  SvCUR_set (enc.sv, enc.cur - SvPVX (enc.sv));

  if (enc.flags & F_SHRINK)
    shrink (enc.sv);

  return enc.sv;
}

/////////////////////////////////////////////////////////////////////////////

#define WS \
  for (;;)                              \
    {                                   \
      char ch = *dec->cur;              \
      if (ch > 0x20                     \
          || (ch != 0x20 && ch != 0x0a && ch != 0x0d && ch != 0x09)) \
        break;                          \
      ++dec->cur;                       \
    }

#define ERR(reason) SB dec->err = reason; goto fail; SE
#define EXPECT_CH(ch) SB \
  if (*dec->cur != ch)          \
    ERR (# ch " expected");     \
  ++dec->cur;                   \
  SE

static SV *decode_sv (dec_t *dec);

static signed char decode_hexdigit[256];

static UV
decode_4hex (dec_t *dec)
{
  signed char d1, d2, d3, d4;

  d1 = decode_hexdigit [((unsigned char *)dec->cur) [0]];
  if (d1 < 0) ERR ("four hexadecimal digits expected");
  d2 = decode_hexdigit [((unsigned char *)dec->cur) [1]];
  if (d2 < 0) ERR ("four hexadecimal digits expected");
  d3 = decode_hexdigit [((unsigned char *)dec->cur) [2]];
  if (d3 < 0) ERR ("four hexadecimal digits expected");
  d4 = decode_hexdigit [((unsigned char *)dec->cur) [3]];
  if (d4 < 0) ERR ("four hexadecimal digits expected");

  dec->cur += 4;

  return ((UV)d1) << 12
       | ((UV)d2) <<  8
       | ((UV)d3) <<  4
       | ((UV)d4);

fail:
  return (UV)-1;
}

#define APPEND_GROW(n) SB \
  if (cur + (n) >= end)                         \
    {                                           \
      STRLEN ofs = cur - SvPVX (sv);            \
      SvGROW (sv, ofs + (n) + 1);               \
      cur = SvPVX (sv) + ofs;                   \
      end = SvEND (sv);                         \
    }                                           \
  SE

#define APPEND_CH(ch) SB \
  APPEND_GROW (1);      \
  *cur++ = (ch);        \
  SE

static SV *
decode_str (dec_t *dec)
{
  SV *sv = NEWSV (0,2);
  int utf8 = 0;
  char *cur = SvPVX (sv);
  char *end = SvEND (sv);

  for (;;)
    {
      unsigned char ch = *(unsigned char *)dec->cur;

      if (ch == '"')
        break;
      else if (ch == '\\')
        {
          switch (*++dec->cur)
            {
              case '\\':
              case '/':
              case '"': APPEND_CH (*dec->cur++); break;

              case 'b': APPEND_CH ('\010'); ++dec->cur; break;
              case 't': APPEND_CH ('\011'); ++dec->cur; break;
              case 'n': APPEND_CH ('\012'); ++dec->cur; break;
              case 'f': APPEND_CH ('\014'); ++dec->cur; break;
              case 'r': APPEND_CH ('\015'); ++dec->cur; break;

              case 'u':
                {
                  UV lo, hi;
                  ++dec->cur;

                  hi = decode_4hex (dec);
                  if (hi == (UV)-1)
                    goto fail;

                  // possibly a surrogate pair
                  if (hi >= 0xd800 && hi < 0xdc00)
                    {
                      if (dec->cur [0] != '\\' || dec->cur [1] != 'u')
                        ERR ("missing low surrogate character in surrogate pair");

                      dec->cur += 2;

                      lo = decode_4hex (dec);
                      if (lo == (UV)-1)
                        goto fail;

                      if (lo < 0xdc00 || lo >= 0xe000)
                        ERR ("surrogate pair expected");

                      hi = (hi - 0xD800) * 0x400 + (lo - 0xDC00) + 0x10000;
                    }
                  else if (hi >= 0xdc00 && hi < 0xe000)
                    ERR ("missing high surrogate character in surrogate pair");

                  if (hi >= 0x80)
                    {
                      utf8 = 1;

                      APPEND_GROW (4); // at most 4 bytes for 21 bits
                      cur = (char *)uvuni_to_utf8_flags (cur, hi, 0);
                    }
                  else
                    APPEND_CH (hi);
                }
                break;

              default:
                --dec->cur;
                ERR ("illegal backslash escape sequence in string");
            }
        }
      else if (ch >= 0x20 && ch <= 0x7f)
        APPEND_CH (*dec->cur++);
      else if (ch >= 0x80)
        {
          STRLEN clen;
          UV uch = utf8n_to_uvuni (dec->cur, dec->end - dec->cur, &clen, UTF8_CHECK_ONLY);
          if (clen == (STRLEN)-1)
            ERR ("malformed UTF-8 character in JSON string");

          APPEND_GROW (clen);
          do
            {
              *cur++ = *dec->cur++;
            }
          while (--clen);

          utf8 = 1;
        }
      else if (dec->cur == dec->end)
        ERR ("unexpected end of string while parsing json string");
      else
        ERR ("invalid character encountered");
    }

  ++dec->cur;

  SvCUR_set (sv, cur - SvPVX (sv));

  SvPOK_only (sv);
  *SvEND (sv) = 0;

  if (utf8)
    SvUTF8_on (sv);

  if (dec->flags & F_SHRINK)
    shrink (sv);

  return sv;

fail:
  SvREFCNT_dec (sv);
  return 0;
}

static SV *
decode_num (dec_t *dec)
{
  int is_nv = 0;
  char *start = dec->cur;

  // [minus]
  if (*dec->cur == '-')
    ++dec->cur;

  if (*dec->cur == '0')
    {
      ++dec->cur;
      if (*dec->cur >= '0' && *dec->cur <= '9')
         ERR ("malformed number (leading zero must not be followed by another digit)");
    }
  else if (*dec->cur < '0' || *dec->cur > '9')
    ERR ("malformed number (no digits after initial minus)");
  else
    do
      {
        ++dec->cur;
      }
    while (*dec->cur >= '0' && *dec->cur <= '9');

  // [frac]
  if (*dec->cur == '.')
    {
      ++dec->cur;

      if (*dec->cur < '0' || *dec->cur > '9')
        ERR ("malformed number (no digits after decimal point)");

      do
        {
          ++dec->cur;
        }
      while (*dec->cur >= '0' && *dec->cur <= '9');

      is_nv = 1;
    }

  // [exp]
  if (*dec->cur == 'e' || *dec->cur == 'E')
    {
      ++dec->cur;

      if (*dec->cur == '-' || *dec->cur == '+')
        ++dec->cur;

      if (*dec->cur < '0' || *dec->cur > '9')
        ERR ("malformed number (no digits after exp sign)");

      do
        {
          ++dec->cur;
        }
      while (*dec->cur >= '0' && *dec->cur <= '9');

      is_nv = 1;
    }

  if (!is_nv)
    {
      UV uv;
      int numtype = grok_number (start, dec->cur - start, &uv);
      if (numtype & IS_NUMBER_IN_UV)
        if (numtype & IS_NUMBER_NEG)
          {
            if (uv < (UV)IV_MIN)
              return newSViv (-(IV)uv);
          }
        else
          return newSVuv (uv);
    }

  return newSVnv (Atof (start));

fail:
  return 0;
}

static SV *
decode_av (dec_t *dec)
{
  AV *av = newAV ();

  WS;
  if (*dec->cur == ']')
    ++dec->cur;
  else
    for (;;)
      {
        SV *value;

        value = decode_sv (dec);
        if (!value)
          goto fail;

        av_push (av, value);

        WS;

        if (*dec->cur == ']')
          {
            ++dec->cur;
            break;
          }
        
        if (*dec->cur != ',')
          ERR (", or ] expected while parsing array");

        ++dec->cur;
      }

  return newRV_noinc ((SV *)av);

fail:
  SvREFCNT_dec (av);
  return 0;
}

static SV *
decode_hv (dec_t *dec)
{
  HV *hv = newHV ();

  WS;
  if (*dec->cur == '}')
    ++dec->cur;
  else
    for (;;)
      {
        SV *key, *value;

        WS; EXPECT_CH ('"');

        key = decode_str (dec);
        if (!key)
          goto fail;

        WS; EXPECT_CH (':');

        value = decode_sv (dec);
        if (!value)
          {
            SvREFCNT_dec (key);
            goto fail;
          }

        //TODO: optimise
        hv_store_ent (hv, key, value, 0);

        WS;

        if (*dec->cur == '}')
          {
            ++dec->cur;
            break;
          }

        if (*dec->cur != ',')
          ERR (", or } expected while parsing object/hash");

        ++dec->cur;
      }

  return newRV_noinc ((SV *)hv);

fail:
  SvREFCNT_dec (hv);
  return 0;
}

static SV *
decode_sv (dec_t *dec)
{
  WS;
  switch (*dec->cur)
    {
      case '"': ++dec->cur; return decode_str (dec); 
      case '[': ++dec->cur; return decode_av (dec); 
      case '{': ++dec->cur; return decode_hv (dec);

      case '-':
      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
        return decode_num (dec);

      case 't':
        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "true", 4))
          {
            dec->cur += 4;
            return newSViv (1);
          }
        else
          ERR ("'true' expected");

        break;

      case 'f':
        if (dec->end - dec->cur >= 5 && !memcmp (dec->cur, "false", 5))
          {
            dec->cur += 5;
            return newSViv (0);
          }
        else
          ERR ("'false' expected");

        break;

      case 'n':
        if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "null", 4))
          {
            dec->cur += 4;
            return newSVsv (&PL_sv_undef);
          }
        else
          ERR ("'null' expected");

        break;

      default:
        ERR ("malformed json string, neither array, object, number, string or atom");
        break;
    }

fail:
  return 0;
}

static SV *
decode_json (SV *string, UV flags)
{
  SV *sv;

  if (flags & F_UTF8)
    sv_utf8_downgrade (string, 0);
  else
    sv_utf8_upgrade (string);

  SvGROW (string, SvCUR (string) + 1); // should basically be a NOP

  dec_t dec;
  dec.flags = flags;
  dec.cur   = SvPVX (string);
  dec.end   = SvEND (string);
  dec.err   = 0;

  sv = decode_sv (&dec);

  if (!sv)
    {
      IV offset = dec.flags & F_UTF8
                  ? dec.cur - SvPVX (string)
                  : utf8_distance (dec.cur, SvPVX (string));
      SV *uni = sv_newmortal ();

      // horrible hack to silence warning inside pv_uni_display
      COP cop = *PL_curcop;
      cop.cop_warnings = pWARN_NONE;
      ENTER;
      SAVEVPTR (PL_curcop);
      PL_curcop = &cop;
      pv_uni_display (uni, dec.cur, dec.end - dec.cur, 20, UNI_DISPLAY_QQ);
      LEAVE;

      croak ("%s, at character offset %d (%s)",
             dec.err,
             (int)offset,
             dec.cur != dec.end ? SvPV_nolen (uni) : "(end of string)");
    }

  sv = sv_2mortal (sv);

  if (!(dec.flags & F_ALLOW_NONREF) && !SvROK (sv))
    croak ("JSON text must be an object or array (but found number, string, true, false or null, use allow_nonref to allow this)");

  return sv;
}

MODULE = JSON::XS               PACKAGE = JSON::XS

BOOT:
{
        int i;

        memset (decode_hexdigit, 0xff, 256);
        for (i = 10; i--; )
          decode_hexdigit ['0' + i] = i;

        for (i = 7; i--; )
          {
            decode_hexdigit ['a' + i] = 10 + i;
            decode_hexdigit ['A' + i] = 10 + i;
          }

        json_stash = gv_stashpv ("JSON::XS", 1);
}

PROTOTYPES: DISABLE

SV *new (char *dummy)
        CODE:
        RETVAL = sv_bless (newRV_noinc (newSVuv (F_DEFAULT)), json_stash);
        OUTPUT:
        RETVAL

SV *ascii (SV *self, int enable = 1)
        ALIAS:
        ascii        = F_ASCII
        utf8         = F_UTF8
        indent       = F_INDENT
        canonical    = F_CANONICAL
        space_before = F_SPACE_BEFORE
        space_after  = F_SPACE_AFTER
        pretty       = F_PRETTY
        allow_nonref = F_ALLOW_NONREF
        shrink       = F_SHRINK
        CODE:
{
        UV *uv = SvJSON (self);
        if (enable)
          *uv |=  ix;
        else
          *uv &= ~ix;

        RETVAL = newSVsv (self);
}
        OUTPUT:
        RETVAL

void encode (SV *self, SV *scalar)
        PPCODE:
        XPUSHs (encode_json (scalar, *SvJSON (self)));

void decode (SV *self, SV *jsonstr)
        PPCODE:
        XPUSHs (decode_json (jsonstr, *SvJSON (self)));

PROTOTYPES: ENABLE

void to_json (SV *scalar)
        PPCODE:
        XPUSHs (encode_json (scalar, F_UTF8));

void from_json (SV *jsonstr)
        PPCODE:
        XPUSHs (decode_json (jsonstr, F_UTF8));

Revision:	1.11
Committed:	Sat Mar 24 19:42:14 2007 UTC (17 years, 1 month ago) by root
Branch:	MAIN
CVS Tags:	rel-0_5
Changes since 1.10:	+2 -2 lines
Log Message:	* empty log message *
#	Content
1	#include "EXTERN.h"
2	#include "perl.h"
3	#include "XSUB.h"
4
5	#include "assert.h"
6	#include "string.h"
7	#include "stdlib.h"
8
9	#define F_ASCII 0x00000001
10	#define F_UTF8 0x00000002
11	#define F_INDENT 0x00000004
12	#define F_CANONICAL 0x00000008
13	#define F_SPACE_BEFORE 0x00000010
14	#define F_SPACE_AFTER 0x00000020
15	#define F_ALLOW_NONREF 0x00000080
16	#define F_SHRINK 0x00000100
17
18	#define F_PRETTY F_INDENT \| F_SPACE_BEFORE \| F_SPACE_AFTER
19	#define F_DEFAULT 0
20
21	#define INIT_SIZE 32 // initial scalar size to be allocated
22
23	#define SB do {
24	#define SE } while (0)
25
26	static HV *json_stash;
27
28	// structure used for encoding JSON
29	typedef struct
30	{
31	char *cur;
32	STRLEN len; // SvLEN (sv)
33	char *end; // SvEND (sv)
34	SV *sv;
35	UV flags;
36	int max_recurse;
37	int indent;
38	} enc_t;
39
40	// structure used for decoding JSON
41	typedef struct
42	{
43	char *cur;
44	char *end;
45	const char *err;
46	UV flags;
47	} dec_t;
48
49	static UV *
50	SvJSON (SV *sv)
51	{
52	if (!(SvROK (sv) && SvOBJECT (SvRV (sv)) && SvSTASH (SvRV (sv)) == json_stash))
53	croak ("object is not of type JSON::XS");
54
55	return &SvUVX (SvRV (sv));
56	}
57
58	static void
59	shrink (SV *sv)
60	{
61	sv_utf8_downgrade (sv, 1);
62	#ifdef SvPV_shrink_to_cur
63	SvPV_shrink_to_cur (sv);
64	#endif
65	}
66
67	/////////////////////////////////////////////////////////////////////////////
68
69	static void
70	need (enc_t *enc, STRLEN len)
71	{
72	if (enc->cur + len >= enc->end)
73	{
74	STRLEN cur = enc->cur - SvPVX (enc->sv);
75	SvGROW (enc->sv, cur + len + 1);
76	enc->cur = SvPVX (enc->sv) + cur;
77	enc->end = SvPVX (enc->sv) + SvLEN (enc->sv);
78	}
79	}
80
81	static void
82	encode_ch (enc_t *enc, char ch)
83	{
84	need (enc, 1);
85	*enc->cur++ = ch;
86	}
87
88	static void
89	encode_str (enc_t enc, char str, STRLEN len, int is_utf8)
90	{
91	char *end = str + len;
92
93	need (enc, len);
94
95	while (str < end)
96	{
97	unsigned char ch = (unsigned char )str;
98
99	if (ch >= 0x20 && ch < 0x80) // most common case
100	{
101	if (ch == '"') // but with slow exceptions
102	{
103	need (enc, len += 1);
104	*enc->cur++ = '\\';
105	*enc->cur++ = '"';
106	}
107	else if (ch == '\\')
108	{
109	need (enc, len += 1);
110	*enc->cur++ = '\\';
111	*enc->cur++ = '\\';
112	}
113	else
114	*enc->cur++ = ch;
115
116	++str;
117	}
118	else
119	{
120	switch (ch)
121	{
122	case '\010': need (enc, len += 1); enc->cur++ = '\\'; enc->cur++ = 'b'; ++str; break;
123	case '\011': need (enc, len += 1); enc->cur++ = '\\'; enc->cur++ = 't'; ++str; break;
124	case '\012': need (enc, len += 1); enc->cur++ = '\\'; enc->cur++ = 'n'; ++str; break;
125	case '\014': need (enc, len += 1); enc->cur++ = '\\'; enc->cur++ = 'f'; ++str; break;
126	case '\015': need (enc, len += 1); enc->cur++ = '\\'; enc->cur++ = 'r'; ++str; break;
127
128	default:
129	{
130	STRLEN clen;
131	UV uch;
132
133	if (is_utf8)
134	{
135	uch = utf8n_to_uvuni (str, end - str, &clen, UTF8_CHECK_ONLY);
136	if (clen == (STRLEN)-1)
137	croak ("malformed or illegal unicode character in string [%.11s], cannot convert to JSON", str);
138	}
139	else
140	{
141	uch = ch;
142	clen = 1;
143	}
144
145	if (uch > 0x10FFFFUL)
146	croak ("out of range codepoint (0x%lx) encountered, unrepresentable in JSON", (unsigned long)uch);
147
148	if (uch < 0x80 \|\| enc->flags & F_ASCII)
149	{
150	if (uch > 0xFFFFUL)
151	{
152	need (enc, len += 11);
153	sprintf (enc->cur, "\\u%04x\\u%04x",
154	(int)((uch - 0x10000) / 0x400 + 0xD800),
155	(int)((uch - 0x10000) % 0x400 + 0xDC00));
156	enc->cur += 12;
157	}
158	else
159	{
160	static char hexdigit [16] = "0123456789abcdef";
161	need (enc, len += 5);
162	*enc->cur++ = '\\';
163	*enc->cur++ = 'u';
164	*enc->cur++ = hexdigit [ uch >> 12 ];
165	*enc->cur++ = hexdigit [(uch >> 8) & 15];
166	*enc->cur++ = hexdigit [(uch >> 4) & 15];
167	*enc->cur++ = hexdigit [(uch >> 0) & 15];
168	}
169
170	str += clen;
171	}
172	else if (is_utf8)
173	{
174	need (enc, len += clen);
175	do
176	{
177	enc->cur++ = str++;
178	}
179	while (--clen);
180	}
181	else
182	{
183	need (enc, len += 10); // never more than 11 bytes needed
184	enc->cur = uvuni_to_utf8_flags (enc->cur, uch, 0);
185	++str;
186	}
187	}
188	}
189	}
190
191	--len;
192	}
193	}
194
195	#define INDENT SB \
196	if (enc->flags & F_INDENT) \
197	{ \
198	int i_; \
199	need (enc, enc->indent); \
200	for (i_ = enc->indent * 3; i_--; )\
201	encode_ch (enc, ' '); \
202	} \
203	SE
204
205	#define SPACE SB need (enc, 1); encode_ch (enc, ' '); SE
206	#define NL SB if (enc->flags & F_INDENT) { need (enc, 1); encode_ch (enc, '\n'); } SE
207	#define COMMA SB \
208	encode_ch (enc, ','); \
209	if (enc->flags & F_INDENT) \
210	NL; \
211	else if (enc->flags & F_SPACE_AFTER) \
212	SPACE; \
213	SE
214
215	static void encode_sv (enc_t enc, SV sv);
216
217	static void
218	encode_av (enc_t enc, AV av)
219	{
220	int i, len = av_len (av);
221
222	encode_ch (enc, '['); NL;
223	++enc->indent;
224
225	for (i = 0; i <= len; ++i)
226	{
227	INDENT;
228	encode_sv (enc, *av_fetch (av, i, 0));
229
230	if (i < len)
231	COMMA;
232	}
233
234	NL;
235
236	--enc->indent;
237	INDENT; encode_ch (enc, ']');
238	}
239
240	static void
241	encode_he (enc_t enc, HE he)
242	{
243	encode_ch (enc, '"');
244
245	if (HeKLEN (he) == HEf_SVKEY)
246	{
247	SV *sv = HeSVKEY (he);
248	STRLEN len;
249	char *str;
250
251	SvGETMAGIC (sv);
252	str = SvPV (sv, len);
253
254	encode_str (enc, str, len, SvUTF8 (sv));
255	}
256	else
257	encode_str (enc, HeKEY (he), HeKLEN (he), HeKUTF8 (he));
258
259	encode_ch (enc, '"');
260
261	if (enc->flags & F_SPACE_BEFORE) SPACE;
262	encode_ch (enc, ':');
263	if (enc->flags & F_SPACE_AFTER ) SPACE;
264	encode_sv (enc, HeVAL (he));
265	}
266
267	// compare hash entries, used when all keys are bytestrings
268	static int
269	he_cmp_fast (const void a_, const void b_)
270	{
271	int cmp;
272
273	HE a = (HE **)a_;
274	HE b = (HE **)b_;
275
276	STRLEN la = HeKLEN (a);
277	STRLEN lb = HeKLEN (b);
278
279	if (!(cmp = memcmp (HeKEY (a), HeKEY (b), la < lb ? la : lb)))
280	cmp = la - lb;
281
282	return cmp;
283	}
284
285	// compare hash entries, used when some keys are sv's or utf-x
286	static int
287	he_cmp_slow (const void a, const void b)
288	{
289	return sv_cmp (HeSVKEY_force ((HE )a), HeSVKEY_force ((HE **)b));
290	}
291
292	static void
293	encode_hv (enc_t enc, HV hv)
294	{
295	int count, i;
296
297	encode_ch (enc, '{'); NL; ++enc->indent;
298
299	if ((count = hv_iterinit (hv)))
300	{
301	// for canonical output we have to sort by keys first
302	// actually, this is mostly due to the stupid so-called
303	// security workaround added somewhere in 5.8.x.
304	// that randomises hash orderings
305	if (enc->flags & F_CANONICAL)
306	{
307	HE he, hes [count];
308	int fast = 1;
309
310	i = 0;
311	while ((he = hv_iternext (hv)))
312	{
313	hes [i++] = he;
314	if (HeKLEN (he) < 0 \|\| HeKUTF8 (he))
315	fast = 0;
316	}
317
318	assert (i == count);
319
320	if (fast)
321	qsort (hes, count, sizeof (HE *), he_cmp_fast);
322	else
323	{
324	// hack to forcefully disable "use bytes"
325	COP cop = *PL_curcop;
326	cop.op_private = 0;
327
328	ENTER;
329	SAVETMPS;
330
331	SAVEVPTR (PL_curcop);
332	PL_curcop = &cop;
333
334	qsort (hes, count, sizeof (HE *), he_cmp_slow);
335
336	FREETMPS;
337	LEAVE;
338	}
339
340	for (i = 0; i < count; ++i)
341	{
342	INDENT;
343	encode_he (enc, hes [i]);
344
345	if (i < count - 1)
346	COMMA;
347	}
348
349	NL;
350	}
351	else
352	{
353	SV *sv;
354	HE *he = hv_iternext (hv);
355
356	for (;;)
357	{
358	INDENT;
359	encode_he (enc, he);
360
361	if (!(he = hv_iternext (hv)))
362	break;
363
364	COMMA;
365	}
366
367	NL;
368	}
369	}
370
371	--enc->indent; INDENT; encode_ch (enc, '}');
372	}
373
374	static void
375	encode_sv (enc_t enc, SV sv)
376	{
377	SvGETMAGIC (sv);
378
379	if (SvPOKp (sv))
380	{
381	STRLEN len;
382	char *str = SvPV (sv, len);
383	encode_ch (enc, '"');
384	encode_str (enc, str, len, SvUTF8 (sv));
385	encode_ch (enc, '"');
386	}
387	else if (SvNOKp (sv))
388	{
389	need (enc, NV_DIG + 32);
390	Gconvert (SvNVX (sv), NV_DIG, 0, enc->cur);
391	enc->cur += strlen (enc->cur);
392	}
393	else if (SvIOKp (sv))
394	{
395	need (enc, 64);
396	enc->cur +=
397	SvIsUV(sv)
398	? snprintf (enc->cur, 64, "%"UVuf, (UV)SvUVX (sv))
399	: snprintf (enc->cur, 64, "%"IVdf, (IV)SvIVX (sv));
400	}
401	else if (SvROK (sv))
402	{
403	SV *rv = SvRV (sv);
404
405	if (!--enc->max_recurse)
406	croak ("data structure too deep (hit recursion limit)");
407
408	switch (SvTYPE (rv))
409	{
410	case SVt_PVAV: encode_av (enc, (AV *)rv); break;
411	case SVt_PVHV: encode_hv (enc, (HV *)rv); break;
412
413	default:
414	croak ("encountered %s, but JSON can only represent references to arrays or hashes",
415	SvPV_nolen (sv));
416	}
417	}
418	else if (!SvOK (sv))
419	encode_str (enc, "null", 4, 0);
420	else
421	croak ("encountered perl type (%s,0x%x) that JSON cannot handle, you might want to report this",
422	SvPV_nolen (sv), SvFLAGS (sv));
423	}
424
425	static SV *
426	encode_json (SV *scalar, UV flags)
427	{
428	if (!(flags & F_ALLOW_NONREF) && !SvROK (scalar))
429	croak ("hash- or arrayref expected (not a simple scalar, use allow_nonref to allow this)");
430
431	enc_t enc;
432	enc.flags = flags;
433	enc.sv = sv_2mortal (NEWSV (0, INIT_SIZE));
434	enc.cur = SvPVX (enc.sv);
435	enc.end = SvEND (enc.sv);
436	enc.max_recurse = 0;
437	enc.indent = 0;
438
439	SvPOK_only (enc.sv);
440	encode_sv (&enc, scalar);
441
442	if (!(flags & (F_ASCII \| F_UTF8)))
443	SvUTF8_on (enc.sv);
444
445	SvCUR_set (enc.sv, enc.cur - SvPVX (enc.sv));
446
447	if (enc.flags & F_SHRINK)
448	shrink (enc.sv);
449
450	return enc.sv;
451	}
452
453	/////////////////////////////////////////////////////////////////////////////
454
455	#define WS \
456	for (;;) \
457	{ \
458	char ch = *dec->cur; \
459	if (ch > 0x20 \
460	\|\| (ch != 0x20 && ch != 0x0a && ch != 0x0d && ch != 0x09)) \
461	break; \
462	++dec->cur; \
463	}
464
465	#define ERR(reason) SB dec->err = reason; goto fail; SE
466	#define EXPECT_CH(ch) SB \
467	if (*dec->cur != ch) \
468	ERR (# ch " expected"); \
469	++dec->cur; \
470	SE
471
472	static SV decode_sv (dec_t dec);
473
474	static signed char decode_hexdigit[256];
475
476	static UV
477	decode_4hex (dec_t *dec)
478	{
479	signed char d1, d2, d3, d4;
480
481	d1 = decode_hexdigit [((unsigned char *)dec->cur) [0]];
482	if (d1 < 0) ERR ("four hexadecimal digits expected");
483	d2 = decode_hexdigit [((unsigned char *)dec->cur) [1]];
484	if (d2 < 0) ERR ("four hexadecimal digits expected");
485	d3 = decode_hexdigit [((unsigned char *)dec->cur) [2]];
486	if (d3 < 0) ERR ("four hexadecimal digits expected");
487	d4 = decode_hexdigit [((unsigned char *)dec->cur) [3]];
488	if (d4 < 0) ERR ("four hexadecimal digits expected");
489
490	dec->cur += 4;
491
492	return ((UV)d1) << 12
493	\| ((UV)d2) << 8
494	\| ((UV)d3) << 4
495	\| ((UV)d4);
496
497	fail:
498	return (UV)-1;
499	}
500
501	#define APPEND_GROW(n) SB \
502	if (cur + (n) >= end) \
503	{ \
504	STRLEN ofs = cur - SvPVX (sv); \
505	SvGROW (sv, ofs + (n) + 1); \
506	cur = SvPVX (sv) + ofs; \
507	end = SvEND (sv); \
508	} \
509	SE
510
511	#define APPEND_CH(ch) SB \
512	APPEND_GROW (1); \
513	*cur++ = (ch); \
514	SE
515
516	static SV *
517	decode_str (dec_t *dec)
518	{
519	SV *sv = NEWSV (0,2);
520	int utf8 = 0;
521	char *cur = SvPVX (sv);
522	char *end = SvEND (sv);
523
524	for (;;)
525	{
526	unsigned char ch = (unsigned char )dec->cur;
527
528	if (ch == '"')
529	break;
530	else if (ch == '\\')
531	{
532	switch (*++dec->cur)
533	{
534	case '\\':
535	case '/':
536	case '"': APPEND_CH (*dec->cur++); break;
537
538	case 'b': APPEND_CH ('\010'); ++dec->cur; break;
539	case 't': APPEND_CH ('\011'); ++dec->cur; break;
540	case 'n': APPEND_CH ('\012'); ++dec->cur; break;
541	case 'f': APPEND_CH ('\014'); ++dec->cur; break;
542	case 'r': APPEND_CH ('\015'); ++dec->cur; break;
543
544	case 'u':
545	{
546	UV lo, hi;
547	++dec->cur;
548
549	hi = decode_4hex (dec);
550	if (hi == (UV)-1)
551	goto fail;
552
553	// possibly a surrogate pair
554	if (hi >= 0xd800 && hi < 0xdc00)
555	{
556	if (dec->cur [0] != '\\' \|\| dec->cur [1] != 'u')
557	ERR ("missing low surrogate character in surrogate pair");
558
559	dec->cur += 2;
560
561	lo = decode_4hex (dec);
562	if (lo == (UV)-1)
563	goto fail;
564
565	if (lo < 0xdc00 \|\| lo >= 0xe000)
566	ERR ("surrogate pair expected");
567
568	hi = (hi - 0xD800) * 0x400 + (lo - 0xDC00) + 0x10000;
569	}
570	else if (hi >= 0xdc00 && hi < 0xe000)
571	ERR ("missing high surrogate character in surrogate pair");
572
573	if (hi >= 0x80)
574	{
575	utf8 = 1;
576
577	APPEND_GROW (4); // at most 4 bytes for 21 bits
578	cur = (char *)uvuni_to_utf8_flags (cur, hi, 0);
579	}
580	else
581	APPEND_CH (hi);
582	}
583	break;
584
585	default:
586	--dec->cur;
587	ERR ("illegal backslash escape sequence in string");
588	}
589	}
590	else if (ch >= 0x20 && ch <= 0x7f)
591	APPEND_CH (*dec->cur++);
592	else if (ch >= 0x80)
593	{
594	STRLEN clen;
595	UV uch = utf8n_to_uvuni (dec->cur, dec->end - dec->cur, &clen, UTF8_CHECK_ONLY);
596	if (clen == (STRLEN)-1)
597	ERR ("malformed UTF-8 character in JSON string");
598
599	APPEND_GROW (clen);
600	do
601	{
602	cur++ = dec->cur++;
603	}
604	while (--clen);
605
606	utf8 = 1;
607	}
608	else if (dec->cur == dec->end)
609	ERR ("unexpected end of string while parsing json string");
610	else
611	ERR ("invalid character encountered");
612	}
613
614	++dec->cur;
615
616	SvCUR_set (sv, cur - SvPVX (sv));
617
618	SvPOK_only (sv);
619	*SvEND (sv) = 0;
620
621	if (utf8)
622	SvUTF8_on (sv);
623
624	if (dec->flags & F_SHRINK)
625	shrink (sv);
626
627	return sv;
628
629	fail:
630	SvREFCNT_dec (sv);
631	return 0;
632	}
633
634	static SV *
635	decode_num (dec_t *dec)
636	{
637	int is_nv = 0;
638	char *start = dec->cur;
639
640	// [minus]
641	if (*dec->cur == '-')
642	++dec->cur;
643
644	if (*dec->cur == '0')
645	{
646	++dec->cur;
647	if (dec->cur >= '0' && dec->cur <= '9')
648	ERR ("malformed number (leading zero must not be followed by another digit)");
649	}
650	else if (dec->cur < '0' \|\| dec->cur > '9')
651	ERR ("malformed number (no digits after initial minus)");
652	else
653	do
654	{
655	++dec->cur;
656	}
657	while (dec->cur >= '0' && dec->cur <= '9');
658
659	// [frac]
660	if (*dec->cur == '.')
661	{
662	++dec->cur;
663
664	if (dec->cur < '0' \|\| dec->cur > '9')
665	ERR ("malformed number (no digits after decimal point)");
666
667	do
668	{
669	++dec->cur;
670	}
671	while (dec->cur >= '0' && dec->cur <= '9');
672
673	is_nv = 1;
674	}
675
676	// [exp]
677	if (dec->cur == 'e' \|\| dec->cur == 'E')
678	{
679	++dec->cur;
680
681	if (dec->cur == '-' \|\| dec->cur == '+')
682	++dec->cur;
683
684	if (dec->cur < '0' \|\| dec->cur > '9')
685	ERR ("malformed number (no digits after exp sign)");
686
687	do
688	{
689	++dec->cur;
690	}
691	while (dec->cur >= '0' && dec->cur <= '9');
692
693	is_nv = 1;
694	}
695
696	if (!is_nv)
697	{
698	UV uv;
699	int numtype = grok_number (start, dec->cur - start, &uv);
700	if (numtype & IS_NUMBER_IN_UV)
701	if (numtype & IS_NUMBER_NEG)
702	{
703	if (uv < (UV)IV_MIN)
704	return newSViv (-(IV)uv);
705	}
706	else
707	return newSVuv (uv);
708	}
709
710	return newSVnv (Atof (start));
711
712	fail:
713	return 0;
714	}
715
716	static SV *
717	decode_av (dec_t *dec)
718	{
719	AV *av = newAV ();
720
721	WS;
722	if (*dec->cur == ']')
723	++dec->cur;
724	else
725	for (;;)
726	{
727	SV *value;
728
729	value = decode_sv (dec);
730	if (!value)
731	goto fail;
732
733	av_push (av, value);
734
735	WS;
736
737	if (*dec->cur == ']')
738	{
739	++dec->cur;
740	break;
741	}
742
743	if (*dec->cur != ',')
744	ERR (", or ] expected while parsing array");
745
746	++dec->cur;
747	}
748
749	return newRV_noinc ((SV *)av);
750
751	fail:
752	SvREFCNT_dec (av);
753	return 0;
754	}
755
756	static SV *
757	decode_hv (dec_t *dec)
758	{
759	HV *hv = newHV ();
760
761	WS;
762	if (*dec->cur == '}')
763	++dec->cur;
764	else
765	for (;;)
766	{
767	SV key, value;
768
769	WS; EXPECT_CH ('"');
770
771	key = decode_str (dec);
772	if (!key)
773	goto fail;
774
775	WS; EXPECT_CH (':');
776
777	value = decode_sv (dec);
778	if (!value)
779	{
780	SvREFCNT_dec (key);
781	goto fail;
782	}
783
784	//TODO: optimise
785	hv_store_ent (hv, key, value, 0);
786
787	WS;
788
789	if (*dec->cur == '}')
790	{
791	++dec->cur;
792	break;
793	}
794
795	if (*dec->cur != ',')
796	ERR (", or } expected while parsing object/hash");
797
798	++dec->cur;
799	}
800
801	return newRV_noinc ((SV *)hv);
802
803	fail:
804	SvREFCNT_dec (hv);
805	return 0;
806	}
807
808	static SV *
809	decode_sv (dec_t *dec)
810	{
811	WS;
812	switch (*dec->cur)
813	{
814	case '"': ++dec->cur; return decode_str (dec);
815	case '[': ++dec->cur; return decode_av (dec);
816	case '{': ++dec->cur; return decode_hv (dec);
817
818	case '-':
819	case '0': case '1': case '2': case '3': case '4':
820	case '5': case '6': case '7': case '8': case '9':
821	return decode_num (dec);
822
823	case 't':
824	if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "true", 4))
825	{
826	dec->cur += 4;
827	return newSViv (1);
828	}
829	else
830	ERR ("'true' expected");
831
832	break;
833
834	case 'f':
835	if (dec->end - dec->cur >= 5 && !memcmp (dec->cur, "false", 5))
836	{
837	dec->cur += 5;
838	return newSViv (0);
839	}
840	else
841	ERR ("'false' expected");
842
843	break;
844
845	case 'n':
846	if (dec->end - dec->cur >= 4 && !memcmp (dec->cur, "null", 4))
847	{
848	dec->cur += 4;
849	return newSVsv (&PL_sv_undef);
850	}
851	else
852	ERR ("'null' expected");
853
854	break;
855
856	default:
857	ERR ("malformed json string, neither array, object, number, string or atom");
858	break;
859	}
860
861	fail:
862	return 0;
863	}
864
865	static SV *
866	decode_json (SV *string, UV flags)
867	{
868	SV *sv;
869
870	if (flags & F_UTF8)
871	sv_utf8_downgrade (string, 0);
872	else
873	sv_utf8_upgrade (string);
874
875	SvGROW (string, SvCUR (string) + 1); // should basically be a NOP
876
877	dec_t dec;
878	dec.flags = flags;
879	dec.cur = SvPVX (string);
880	dec.end = SvEND (string);
881	dec.err = 0;
882
883	sv = decode_sv (&dec);
884
885	if (!sv)
886	{
887	IV offset = dec.flags & F_UTF8
888	? dec.cur - SvPVX (string)
889	: utf8_distance (dec.cur, SvPVX (string));
890	SV *uni = sv_newmortal ();
891
892	// horrible hack to silence warning inside pv_uni_display
893	COP cop = *PL_curcop;
894	cop.cop_warnings = pWARN_NONE;
895	ENTER;
896	SAVEVPTR (PL_curcop);
897	PL_curcop = &cop;
898	pv_uni_display (uni, dec.cur, dec.end - dec.cur, 20, UNI_DISPLAY_QQ);
899	LEAVE;
900
901	croak ("%s, at character offset %d (%s)",
902	dec.err,
903	(int)offset,
904	dec.cur != dec.end ? SvPV_nolen (uni) : "(end of string)");
905	}
906
907	sv = sv_2mortal (sv);
908
909	if (!(dec.flags & F_ALLOW_NONREF) && !SvROK (sv))
910	croak ("JSON text must be an object or array (but found number, string, true, false or null, use allow_nonref to allow this)");
911
912	return sv;
913	}
914
915	MODULE = JSON::XS PACKAGE = JSON::XS
916
917	BOOT:
918	{
919	int i;
920
921	memset (decode_hexdigit, 0xff, 256);
922	for (i = 10; i--; )
923	decode_hexdigit ['0' + i] = i;
924
925	for (i = 7; i--; )
926	{
927	decode_hexdigit ['a' + i] = 10 + i;
928	decode_hexdigit ['A' + i] = 10 + i;
929	}
930
931	json_stash = gv_stashpv ("JSON::XS", 1);
932	}
933
934	PROTOTYPES: DISABLE
935
936	SV new (char dummy)
937	CODE:
938	RETVAL = sv_bless (newRV_noinc (newSVuv (F_DEFAULT)), json_stash);
939	OUTPUT:
940	RETVAL
941
942	SV ascii (SV self, int enable = 1)
943	ALIAS:
944	ascii = F_ASCII
945	utf8 = F_UTF8
946	indent = F_INDENT
947	canonical = F_CANONICAL
948	space_before = F_SPACE_BEFORE
949	space_after = F_SPACE_AFTER
950	pretty = F_PRETTY
951	allow_nonref = F_ALLOW_NONREF
952	shrink = F_SHRINK
953	CODE:
954	{
955	UV *uv = SvJSON (self);
956	if (enable)
957	*uv \|= ix;
958	else
959	*uv &= ~ix;
960
961	RETVAL = newSVsv (self);
962	}
963	OUTPUT:
964	RETVAL
965
966	void encode (SV self, SV scalar)
967	PPCODE:
968	XPUSHs (encode_json (scalar, *SvJSON (self)));
969
970	void decode (SV self, SV jsonstr)
971	PPCODE:
972	XPUSHs (decode_json (jsonstr, *SvJSON (self)));
973
974	PROTOTYPES: ENABLE
975
976	void to_json (SV *scalar)
977	PPCODE:
978	XPUSHs (encode_json (scalar, F_UTF8));
979
980	void from_json (SV *jsonstr)
981	PPCODE:
982	XPUSHs (decode_json (jsonstr, F_UTF8));
983